There's a definitely a lesson here to run more socialists locally.

For now. When you first build your local bastions, you can later start playing a national role. All large, national movements which we know from history are build on the local organising of unknown and unsung comrades.

You need both. Federal and State government can undermine municipal governments, while some things like labor laws are only defined in the state and federal level.

There's also a capillarity issue, socialist parties are usually small, so they can't organize effectively in every municipality, so they need to focus on a few key regions where their bases are strong.